package com.yimin.Utils;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import static org.springframework.util.FileCopyUtils.BUFFER_SIZE;

public class FileDownUtil {

    /**
     * 压缩目录
     * @param srcDir
     * @param out
     * @param KeepDirStructure
     * @throws RuntimeException
     */
    public static void toZip(String srcDir, OutputStream out, boolean KeepDirStructure) throws RuntimeException {
        long start = System.currentTimeMillis();
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(out);
            File sourceFile = new File(srcDir);
            compress(sourceFile, zos, sourceFile.getName(), KeepDirStructure);
            long end = System.currentTimeMillis();
            System.out.println("压缩完成，耗时：" + (end - start) + " ms");
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }


    /**
     * 下载文件流
     * @param response
     * @param fileName
     * @param inputData
     * @throws IOException
     */
    public static void downloadFile(HttpServletResponse response, String fileName, InputStream inputData) throws IOException {

        BufferedInputStream bins = new BufferedInputStream(inputData);//放到缓冲流里面
        OutputStream outs = response.getOutputStream();//获取文件输出IO流
        BufferedOutputStream bouts = new BufferedOutputStream(outs);
        response.setContentType("application/x-download");
        response.setHeader("Content-disposition", "attachment;filename=" + URLEncoder.encode(fileName, "UTF-8"));
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        //开始向网络传输文件流
        while ((bytesRead = bins.read(buffer, 0, 8192)) != -1) {
            bouts.write(buffer, 0, bytesRead);
        }
        bouts.flush();//这里一定要调用flush()方法
        inputData.close();
        bins.close();
        outs.close();
        bouts.close();

    }



    public static void compress(File sourceFile, ZipOutputStream zos, String name, boolean KeepDirStructure)
            throws Exception {
        byte[] buf = new byte[BUFFER_SIZE];
        if (sourceFile.isFile()) {
            // 向zip输出流中添加一个zip实体，构造器中name为zip实体的文件的名字
            zos.putNextEntry(new ZipEntry(name));
            // copy文件到zip输出流中
            int len;
            FileInputStream in = new FileInputStream(sourceFile);
            while ((len = in.read(buf)) != -1) {
                zos.write(buf, 0, len);
            }
            // Complete the entry
            zos.closeEntry();
            in.close();
        } else {
            File[] listFiles = sourceFile.listFiles();
            if (listFiles == null || listFiles.length == 0) {
                // 需要保留原来的文件结构时,需要对空文件夹进行处理
                if (KeepDirStructure) {
                    // 空文件夹的处理
                    zos.putNextEntry(new ZipEntry(name + "/"));
                    // 没有文件，不需要文件的copy
                    zos.closeEntry();
                }
            } else {
                for (File file : listFiles) {
                    // 判断是否需要保留原来的文件结构
                    if (KeepDirStructure) {
                        // 注意：file.getName()前面需要带上父文件夹的名字加一斜杠,
                        // 不然最后压缩包中就不能保留原来的文件结构,即：所有文件都跑到压缩包根目录下了
                        compress(file, zos, name + "/" + file.getName(), KeepDirStructure);
                    } else {
                        compress(file, zos, file.getName(), KeepDirStructure);
                    }
                }
            }
        }
    }




}
